Epoxy aldimines



EPOXY ALDllVIINES Paul H. Williams, Orinda, and George B. Payne, andPaul 'R. -Van Ess,-Berkeley, Calif., assignors to Shell Oil Company, NewYork, N.Y., a corporation of Dela- -This invention relates to novelepoxy compounds and to a process for preparing them. More specifically,the invention relates to new and useful epoxyimino compounds and to aprocess for preparing them from epoxyaldehydes. Still more particularly,the invention relates to such epoxyimines as are prepared by thereaction between an epoxyaldehyde and an organic amino compound.

Epoxy compounds such as epichlorohydrin are wellknown reactants in thepreparation of such materials as resins. The preparation of suchnitrogen-containing epoxy compounds as epoxyimines from the reaction ofepoxy compounds and amines has not, however, been considered feasiblebecause of the well-known tendency of the epoxy ring to be opened in thecourse of the reaction. For example, when ethylene oxide is reacted withdiethylamine, the ring opens to yield diethylaminoethanol as a product.We have unexpectedly discovered, however, that it is possible to reactepoxy ring-containing compounds of a certain type with amines underconditions whereby the ring is not attacked. The resulting reactionproduct is thus characterized by possession of an intact The epoxyiminocompounds of this invention have a variety of desirable uses. Forexample, the monoepoxyimines are valuable plasticizers and modifiers inpolyepoxy resins. Moreover, since they possess an intact oxirane ring,they are extremely useful as stabilizers in polyvinyl halide-typ resinswhere they inhibit degradation resulting from the release of hydrogenhalide. The polyepoxyimines form useful resinous materials when curedwith such well-known curing agents as anhydrides, acids, or borontriiluoride. By virtue of their possession of a variety of reactivegroups our epoxyimines may be used as chemical intermediates, e.g., asstarting points for the synthesis of such derived chemical products aslubricating oil additives, detergents, surface-active agents,biologically active compounds, and the like.

It is an object of this invention to provide a new class of epoxycompounds. A further object of the invention is the provision ofselectively reacting the carbonyl group of an epoxyaldehyde with aprimary amine to produce novel epoxyimines. It is a further object ofthe invention to provide novel epoxyimino compounds, and a still furtherobject of the invention is to provide a unique process wherebyepoxyaldehydes can be reacted with organic amino compounds to yield theepoxyimines without attack on the epoxy ring. The unique epoxyalkylideneimino compounds resulting from the reaction are yet another object ofthe invention. Other objects of the invention will be apparent from thefollowing 'description thereof.

The invention comprises epoxyimino compounds having at least oneepoxyalkylidene substituent. In the context of this invention, imino isused to denote those com- Patent 2,953,579 li attentedv Sept. 20, 1960ice - 2 pounds having the irnino linkage C=N. Such compounds may bestbedescribed by the formula Where R. is an epoxy alkylidene radical, R isan organic radical, and nis a positive integer.

By epoxyalkylidene radical we mean an alkylidene radical, that is, ,adivalent organic radical derived from an .aliphatic hydrocarbon and fromwhich two hydrogen atoms are, taken from the same carbon atoms, andcontaining an epoxy ring. The epoxy ring, or oxirane ring as it issometimes termed, is characterized by the structure,

7 CL C l I 7 Lee and Neville, Epoxy Resins (McGraw-Hill, 1957), page 6.Since the oxygen atom is connected to two yicinal, or adjacent, carbonatoms, the configuration shown is also sometimes termed thevicinal-epoxy ring. In the epoxyalkylidene radicals of theinvention,'the epoxy ring may be either an internal ring, or it may be aterminal ring, wherein one of the carbon atoms of the ring is a terminalcarbon atom of the epoxyalklidene chain. Since terminal epoxy rings areconsiderably more reactive than are internal epoxy rings,epoxyalkylidene radicals having terminal epoxy rings and less than eightcarbon atoms are preferred in this invention.

,The epoxyimines of our invention can best be understood by consideringthe manner in which they are synthesized. In general, such imines areprepared by reacting an epoxyaldehyde and an organic primary amine attemperatures such that the ring is not attacked.

The epoxyaldehyde reactant includes all compounds characterized by thepossession of both the formyl group CH0 and the epoxy or oxirane groupThese compounds may readily be prepared by the epoxidation ofunsaturated aldehydes. The preferred class of epoxyaldehydes consists ofthose epoxy compounds produced by the oxidation ofalpha,beta-unsaturated aldehydes such as acrolein, crotonaldehyde,methacrolein, tiglic aldehyde, citral, cinamaldehyde, and the like, andthe most preferred epoxyaldehyde is glycidaldehyde, which is prepared bythe oxidation of acrolein. Equally useful in the process of ourinvention are, however, epoxyaldehydes which are prepared from olefinicaldehydes having one or more double bonds further removed from theformyl group. Typical examples of such aldehydes are vinyl acetaldehyde,B-pentenal, 4- pentenal, methyl vinyl acetaldehyde, isopropenylacetaldehyde, citronellal, rhodinal, and 2-phenyl-4-hexenal.

These epoxyaldehydes are reacted in our invention with an organicprimary amine to produce the novel epoxyimines. Such organic aminocompounds consist of organic compounds having at least one primary aminogroup, NH in their constitution. Amines having more than one suchprimary amino group are, of course, included within the scope of ourprocess.

Examples of suitable monoamine reactants, those having the structure RNHinclude the aliphatic amines, including such .alkylamines as methyl,ethyl, butyl, tertbutyl, andlau-rylamines and such alkenylamines asallylamine, methallylarnine, ethallylamine and pentene-Z- amine, aswellas the .cyclic amines such as cyclopentyl andfcyclohexylamine andaniline. Included as well in the suitable primary amine reactants arethe diamines, H NR'NH such as ethylenediamine, trimethylenediamine,hexamethylenediamine, the phenylenediamines,

benzidine, the toluidines, o-toluidene, and such substituted aromaticdiatnines as durenediamine. Organic compounds having more than two aminogroups, such as triaminobenzene, are also within the scope of theinvention.

The amino reactants include, in addition to the hydrocarbon aminocompounds of the preceding paragraph, organic compounds having othersubstituents in addition to the -NH groups. Thus, the primary aminocompounds noted may also have included within the molecule such othergroups as nitro-hydroxy, ether, keto, nitrile, and the like, or halogenatoms. Illustrative of such substituted compounds are chlorallylamine,the aminobenzoic acids, the nitroanilines, sulfanilic acid and itsisomers, the haloanilines, ethanolamine, the aminophenols,o-dianisidine, and the like. Such hetereocyclic primary amines asZ-aminopyridine, N-methyl-Z-piperidineamine, furfurylamine andtetr'ahydrofurfurylamine are also within the scope of organic primaryamine reactants in the invention.

As has been noted, the epoxyaldehyde and the organic amino compound arereacted together in our invention to form the novel imino compoundsdescribed. If desired, the reaction may be conducted in the presence ofdesiccant agents, such as magnesium sulfate, calcium oxide, or the like,or alternatively, the reaction may be conducted at high temperatures andin the presence of liquids which remove water overhead as an azeotrope.We prefer to conduct the reaction between the epoxyaldehyde and theorganic amino compound in a liquid which is a solvent for the reactantsand the product imine, but with which water is not miscible, so that thewater is removed from the locus of the reaction as it forms and withoutthe use of either high temperatures or drying agents. Combinations ofwater-immiscible solvents and drying agents are, of course, within thescope of the in vention. It should be emphasized, however, that theremoval of the product water merely serves to hasten the completion ofthe reaction and, as will be seen, is not a necessary element for thepreparation of our novel epoxyimino compounds.

Examples of the liquids in which the reaction may be conducted includethe parafiins such as those liquid at or below room temperature; thearomatic solvents, such as benzene, toluene and xylene; and such otherorganic liquids as the ethers, including diethyl ether, and acetone. Oneconvenient way of conducting the reaction is to prepare a solution ofthe epoxyaldehyde and one of the organic amino compound in such asolvent as described, and merely mixing these solutions to bring aboutthe production of the epoxyimine. The reaction may, however, beconducted in the absence of solvent if desired.

The reactants may be employed in a wide variety of proportions. A largeexcess of the amine may, dependiug on the solvent and reactionconditions, result in attack on the epoxy ring of the aldehyde, and sowe prefer that approximately stoichiometric amounts of the organic aminocompound and the epoxyaldehyde be employed. By this we mean that about astoichiometric amount of epoxyaldehyde should be used for every -NHgroup of the organic amino compound.

The reaction between the epoxyaldehydes and the organic amino compoundsproceeds satisfactorily at ordinary temperatures and without the needfor catalysts or initiators. While the most convenient temperature rangeforthe reaction to be conducted is between about and about 100 C., thepreferred temperature range is that between about 20 C., that is, roomtemperature, and about 0 C. At temperatures in excess of about 100 C.,while the reaction will proceed, there is some danger tures the reactionrate dacreases and many of the solvents become solids.

2,3-epoxybutyraldehyde+durenediamiue CH3 (llHa CH3 CH2,3-ep0xypentanal+aniline-2,3-epoxy-B-phenylpropionaldehyde+ethylenediamine (OH .@H OH=N a...

glycidaldehyde+2aminopyridine--2,3-epoxy-2-methylbutyraldehyde-l-beta-naphthylamine The followingexamples are intended to illustrate but not limit the embodiments of theinvention as recited in the appended claims. It is therefore to beunderstood that the invention is not to be limited to the specificmaterials or conditions recited therein. Unless otherwise noted, allproportions given in the examples are in parts by weight.

Example I.Preparati0n of N-glycidylidene t-butylamine Clear benzenesolutions containing 0.33 moles of glycidaldehyde and 0.30 moles oftert-butylamine were prepared, and cooled to 10 C. The solutions werethen mixed thoroughly, and water was observed to settle out at once. Themixture was allowed to stand for one hour at 5 C., dried over anhydrousmagnesium sulfate, filtered, and the benzene stripped therefrom.

Upon Claisen distillation, water-white N-glycidylidene t-butylamine wasobtained in 82% yield. The product had a boiling point of 4045 C. at 7-9mm., and its composition was found to be as follows:

Percent Percent Percent Epoxy O H N Value eq./ g.

Calculated for C H 3NO 66.1 10.3 11.0 0.79 Found 66.2 10. 4 10. 9 0. 77

These data corresponded to the compound having the formula CH3 HgCCHOH=N-COHG The imine Was quite stable; a sample heatedon a steam bathfor two hours showed at the end of that time no loss of epoxy content ordevelopment of color.

By using alpha-nap'hthylamine in place of aniline, Nglycidy-lidene-alpha-naphthylamine can be prepared in the same manner.

Example II.Preparatin of N-glycidylidene t-butylamine 5 Example VI.--Preparation of p-(N-glycidylidene)aminoin acetone benzoic acid Asolution of 0.25 moles of t-butylamine in 25 parts of Solutions ofapproximately equirnolar amounts of glyacetone was added portionwisewith swirling to a solution cidaldehyde in diethyl ether andp-aminobenzoic acid in of 0.27 moles of anhydrous glycidaldehyde in 25parts of ether were stirred together overnight at room temperaacetone.Ice bath cooling was used to keep the temperatllfep-( -g y y add wasture of the reaction mixture below 20 C. The mixture tained in 100%yield, having the following composition: was then allowed to stand atroom temperature for about 30 minutes and then Claisen-distilled at roomtempera- Percent Percent Percent New ture and reduced pressure to removethe acetone and the C H N Equiv. Water of reaction.

An 84% yield of N-glycidylidene t-butylamine, having Calculated forcwHvN03. 62.8 4.8 7.3 101 a boiling point of 4550 at 10 mm., was thusobtained, Found demonstrating that the reaction could be conducted evenin the presence of water. which corresponded to the compound having thestructure 20 Example III.-Preparati0n of N-glycidylidene t-butylamine inthe absence of solvent Hi00H0H=NCOOH 0.25 mole of t-butylamine was addeddropwise, with stirring, to 0.28 mole of glycidaldehyde, the reactionExample P y mixture being maintained at a temperature below 20durenediamine C. The mixture was then allowed to stand at room tem- A li f 0.70 ole of glycidaldehyde in 1000 perature for about minutes, andthen Claisen-distilled parts f benzene was stirred with 5 Parts ofanhydrous as 111 p magnesium sulfate and treated portionwise with 0.32 fYleld of N'glycldylldene tbutylamme hzfvlng moles of durenediamine. Themixture was stirred for a bollmg P9 of 40x45, at 8 was thHSPbtamEd, 30about 30 minutes at room temperature and then filtered demonstratlngeXcellcnt yi lds may be Obtained even to remove the olid desiccant UponWeighing the mag. if the reaction is carried out without solvent of anykind. nesium lf t was f d to contain the theoretical amount of water.Example IV'Prepamtmn of N-glyadyhdene ethylamme The filtrate was allowedto stand at room temperature, Using 1116 method described in EXample g yand within about 30 minutes the solid product began to hyde was reactedwith ethylamine. A 69% yield of N- crystallize slowly. After standingovernight, a 54% yield glycidylidene ethylamille Was Obtained- The compond of N,N-bis(glycidylidene) durenediamine was obtained had a boilingpoint of 46-49 C. at 30 mm., a refractive having the followingcomposition: index of 1.43 89 and npon analysis was found to have 40 thefollowmg composmon' Percent Percent Percent Pergcent 5? 53" 5173 52;@3513 Calculated for ONHMNZOZ 70.6 7.4 10.3 eq /100 g, ou d 70. 6 7. 510.2

ciiiiii iif 60.6 9.2 14.1 1.01 1.01 whlch corresponded to the StructureFound 61.0 9.2 13.6 0.97 0.95 0113 OH,

By using epoxybutyraldehyde in place of glycidalde- HO/ OH CHNN=CHOfi'OH hyde, N-(2,3-epoxybutylidene) ethylamine can be prepared inequivalent yield. H3 H3 The compound had a melting point of 155-165" C.Example V.-Preparaz z"0n of N-glycidylidene aniline W l i as our i i ASin the previous experiments, 033 moles of 1. An epoxy aldimine havingthe structural formula hydrous glycidaldehyde in benzene and 0.30 molesof 0 freshly distilled aniline in benzene were reacted at 0 C. Afterdrying and purification, a 94% yield of N-glyk cidylidene aniline wasobtained. The compound had a boiling point of 58-59 C. at 0.13 mm., arefractive index 60 Where 1 Tepl'esents a member of the class consisting0f of 1.5772 and analysis showed the following compohydrogen, methyl, yand p y 2 represents a sition: member of the class consisting ofhydrogen and methyl, and R represents a member, having up to 12 carbonatoms, of the class consisting of the unsubstituted alkyl, Perent gg igg EPOXY alkylene, pyridyl, naphthyl, and phenyl radicals and q./l00 g.Value eq,/1OO carboxy phenyl and methyl-substituted phenylene, and n isa positive integer of from 1 to 2, equal to the valence Calculated forof the radical represented by R g-g g-g g-gg g-gg 2.N-(2,3-epoxypropylidene) -t-butylamine. 3. N-2,3-epoxypropylideneaniline.

4. N-N-bis(2,3-epoxypropylidene)-durene diamine. which correspond to acompound having the structure 5. N-(2,3-epoxypropy1idene)-p-aminobenzoicacid.

0 6. N-2,3-epoxypropylidene ethylamine. CH GH N 76 No references cited.

1. AN EPOXY ALDIMINE HAVING THE STRUCTURAL FORMULA